I am continuing my explorations of the great terminal-based video tool FFmpeg. Now I wanted to see if I could “flatten” a 360-degree video recorded with a Ricoh Theta camera. These cameras contain two fisheye lenses, capturing two 180-degree videos next to each other. This results in video files like shown in the screenshot below.
These files are not very useful to watch or work with, so we need to somehow “flatten” it into a more meaningful video file. I find it cumbersome to do this in the Ricoh mobile phone apps, so have been looking for a simple solution to do it on my computer.
I see that the FFmpeg developers are working on native support for various 360-degree video files. This is implemented in the filter v360, but since it is not in the stable version of FFmpeg yet, I decided to look for something that works right now. Then I came across this blog post, which shows how to do the flattening based on two so-called PGM files that contain information about how the video should be mapped:
ffmpeg -i ricoh_input.mp4 -i xmap_thetaS_1920x960v3.pgm -i ymap_ThetaS_1920x960v3.pgm -q 0 -lavfi "format=pix_fmts=rgb24,remap" remapped.mp4
The end result is a flattened video file, as shown below:
As for where to split up the video (it is a continuous 360-degree video after all) I will have to investigate later.